The present invention relates to a manipulator for guiding devices used for treating heats in furnaces, ladles and the like, e.g., lances for injecting oxygen through a door of an electro-melting furnace. More generally, the invention relates to manipulators for remotely controlling devices to be inserted into vessels of any kind, especially vessels contained in environments, where the working conditions are hazardous.
In metallurgical processes where a metal heat is treated by injection of a gas such as oxygen, a mixture of a gas and a solid material in powder form such as pulverized coal, a liquid, a liquid suspension, or a mixture of a gas and a liquid, such injection is in many cases carried out by using a tubular lance which is inserted into the melt, the gas and/or liquid substance(s) being blown therethrough and into the melt. As for elector-steel furnaces for melting of steel scrap, the scrap is melted in a furnace vessel provided with a cover through which electrodes are lowered down towards the scrap material and the heat. Oxygen is added through one or several lances which are inserted through an opening in the wall of the vessel, e.g., an opening for removal of slag from the heat, and down into the melt. The lance is thereby arranged on a manually drawn car on an adjacent platform, by which its position in the heat also can be roughly adjusted. The disadvantage of this car is that the operating personnel must be positioned close to the furnace, which exposes them to a risk of injuries e.g., due to splashing from the furnace.
The lance can also be arranged on a stand fixed to the furnace platform, whereby the lance is displaceable in its length direction inwardly or outwardly of the furnace through a small door in the furnace wall. The disadvantage of this arrangement is that the lance cannot be lowered down at different angles towards the melt in the furnace.
With the aim of improving the guiding of the lance, a car provided with a feed table for one or several lances has been developed. The feed table can be raised and lowered and can be inclined forward and backwards. The lance can also be fed forward and backwards in its length direction. The disadvantage of this car is the same as for the one described above: the risk of injury to the personnel operating the car.
As regards metallurgical melting furnaces, it also occurs that slag floating on top of the metal heat is removed from the surface of the heat by tilting the furnace so that the slag flows through a door in the furnace wall. During this procedure slag can become frozen in the sides of the door and must be removed with a special device. Such a device can be arranged on a mechanically operated car on the furnace platform in front of the deslagging door. The device is consists of a bar that is provided with a scraper which is inserted into the door and enables the frozen slag to be removed. The disadvantage of known devices is a they are expensive to manufacture and that rather great precision is required during their handling to obtain the desired result. Anothor disadvantage is that remote control of them is difficult to realize.